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# Last update 2022.2.018
#    Hiroyuki Murakami (hir.murakami@gmail.com)
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#--1. Introduction
  This program is to calculate the modified version of the Dynamic Genesis Potential Index (DGPI) developed by Wang and Murakami (2020) as used in Murakami and Wang (2022)..
  The sample code is written in Python2. This code depends on the following Python modules.

  netCDF4
  Matplotlib
  Matplotlib Basemap
  numpy

#--2. File information
  01_compute_DGPI.py  : A Python script to compute DGPI
  02_compute_ENGPI.py : A Python script to compute Emanuel and Nolan's GDPI (ENGPI) 
  03_plot_GPI.py      : A Python script to draw climatological DGPI and ENGPI compared with the observd tropical cyclone geneiss frequency (TCG)

  input_data/besttrack/: Best track tropical cyclone data (1980-2017)
               tcg.nc : Observed monthly TCG
   tcg_climmonthly.nc : Observed climatological monthly TCG

  input_data/reanalysis/: Merged reanalysis data (1980-2017)
           avor850a.nc: Monthly absolute vorticity
                mpi.nc: Monthly potential intensity
                msu.nc: Monthly dudy at 500 hPa
           omega500.nc: Monthly omega at 500 hPa
              rh600.nc: Monthly relative humidity at 600 hPa
             sstanm.nc: Monthly relative SST anomaly
             wshear.nc: Monthly vertical wind shear between 200 hPa and 850 hPa

  output_data/ : Output directory
                  dgpi.nc: Monthly DGPI computed by 01_compute_DGPI.py
      dgpi_climmonthly.nc: Climatological Monthly mean DGPI computed by 01_compute_DGPI.py
                 engpi.nc: Monthly ENDGPI computed by 02_compute_ENGPI.py
     engpi_climmonthly.nc: Climatological Monthly mean ENGPI computed by 02_compute_ENGPI.py

  pic_data/ : Picture directory
     Fig.png : Climatological TCG, ENGPI, and DGPI by 03_plot_GPI.py 

#--3. Note
  The DGPI values are replaced with zero over the domain of 2S-2N latitudes and negative relative SST anomaly (i.e., serve as cut-off).
  Some coefficients for DGPI was modified from the original formlat published in Wang and Murakami (2020). Plsease see Murakami and Wang (2022).

#--Reference 
  Wang, B. and H. Murakami, 2020: Dynamic genesis potential index for diagnosing present-day and future global tropical cyclone genesis. Environ. Res. Lett., 15, 114008.
  Murakami, H. and B. Wang, 2022: Patterns and frequency of projected future tropical cyclone genesis is governed by dynamic effects. Commun. Earth Environ.
